5) The number of moles of MgO produced when 0.20 mole of O, reacts completely in excess Mg(s) is 2Mg(s) + O2(g) â 2MgO(s) A) 0.10 mole. B) 0.20 mole. C) 0.40 mole. D) 0.60 mole. 6) How many grams of MgO are produced when 40.0 grams of O, react completely with excess Mg(s)? 2Mg(s) + O2(g) â 2MgO(s) A) 126 g B) 50.4 g C) 60.8 g D) 101 g 7) If you only have 3.00 moles of methane CH, and 4.00 moles of oxygen, O2 to react and to form carbon dioxide CO, and water H,O which reactant is the limiting reagent? CH,(g) + 20, (g) â CO2 (g) + 2H20(1) A) CH C) CO2 D) H2O